Lexus ES: Check Bus 5 Lines for Short Circuit
DESCRIPTION
There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω.
| Symptom | Trouble Area |
|---|---|
| Resistance between terminals 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω. |
|
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
NOTICE:
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Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
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- Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
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After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.
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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the power switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
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After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
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Before replacing the main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), refer to Registration.
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HINT:
- Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
- When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.
PROCEDURE
| 1. | CHECK FOR SHORT IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) auxiliary battery terminal.
(b) Disconnect the N97 No. 1 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
| *a | Front view of wire harness connector (to No. 1 Junction Connector) | *b | to Central Gateway ECU (Network Gateway ECU) |
| *c | to Headlight ECU Sub-assembly RH | *d | to Outer Mirror Control ECU Assembly RH (w/ Seat Position Memory System) |
| *e | to No. 8 CAN Junction Connector | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| N97-8 (CANH) - N97-19 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | Central gateway ECU (network gateway ECU) |
| N97-9 (CANH) - N97-20 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Headlight ECU sub-assembly RH |
| N97-10 (CANH) - N97-21 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Outer mirror control ECU assembly RH* |
| N97-11 (CANH) - N97-22 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | No. 8 CAN junction connector |
- *: w/ Seat Position Memory System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to central gateway ECU (network gateway ECU)) | B |
| NG (Line to No. 8 CAN junction connector) | C |
| NG (Line to ECU or sensor) | D |
| A | .gif) | REPLACE NO. 1 JUNCTION CONNECTOR |
| C | | GO TO STEP 3 |
| D | | GO TO STEP 6 |
|
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| 2. | CHECK FOR SHORT IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Disconnect the G66 central gateway ECU (network gateway ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
| *a | Front view of wire harness connector (to No. 1 Junction Connector) | *b | to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| N97-8 (CANH) - N97-19 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 1 MΩ or higher |
| OK | | REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
| 3. | CHECK FOR SHORT IN CAN BUS LINES (NO. 8 CAN JUNCTION CONNECTOR) |
(a) Reconnect the N97 No. 1 junction connector.
(b) Disconnect the N101 No. 8 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
| *a | Front view of wire harness connector (to No. 8 CAN Junction Connector) | *b | to Outer Mirror Control ECU Assembly LH (w/ Seat Position Memory System) |
| *c | to Luggage Closer Motor Assembly (w/ Power Trunk Lid System) | *d | to No. 5 CAN Junction Connector |
| *e | to No. 1 Junction Connector | *f | to Position Control ECU Assembly LH (w/ Seat Position Memory System) |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| N101-1 (CANH) - N101-7 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Outer mirror control ECU assembly LH*1 |
| N101-2 (CANH) - N101-8 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Luggage closer motor assembly*2 |
| N101-3 (CANH) - N101-9 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | No. 5 CAN junction connector |
| N101-4 (CANH) - N101-10 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | No. 1 junction connector |
| N101-5 (CANH) - N101-11 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Position control ECU assembly LH*1 |
- *1: w/ Seat Position Memory System
- *2: w/ Power Trunk Lid System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to No. 1 junction connector) | B |
| NG (Line to No. 5 CAN junction connector) | C |
| NG (Line to ECU or sensor) | D |
| A | | REPLACE NO. 8 CAN JUNCTION CONNECTOR |
| B | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR) |
| D | | GO TO STEP 6 |
|
| 4. | CHECK FOR SHORT IN CAN BUS LINES (NO. 5 CAN JUNCTION CONNECTOR) |
(a) Reconnect the N101 No. 8 CAN junction connector.
(b) Disconnect the G97 No. 5 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
| *a | Front view of wire harness connector (to No. 5 CAN Junction Connector) | *b | to Air Conditioning Amplifier Assembly |
| *c | to Certification ECU (Smart Key ECU Assembly) | *d | to Headlight ECU Sub-assembly LH |
| *e | to Main Body ECU (Multiplex Network Body ECU) | *f | to No. 8 CAN Junction Connector |
| *g | to Combination Meter Assembly | *h | to Meter Mirror Sub-assembly (w/ Headup Display System) |
| *i | to Multiplex Tilt and Telescopic ECU (w/ Power Tilt and Power Telescopic System) | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| G97-3 (CANH) - G97-14 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Air conditioning amplifier assembly |
| G97-4 (CANH) - G97-15 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Certification ECU (smart key ECU assembly) |
| G97-5 (CANH) - G97-16 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Headlight ECU sub-assembly LH |
| G97-6 (CANH) - G97-17 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Main body ECU (multiplex network body ECU) |
| G97-7 (CANH) - G97-18 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | No. 8 CAN junction connector |
| G97-8 (CANH) - G97-19 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 108 to 132 Ω | Combination meter assembly |
| G97-9 (CANH) - G97-20 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Meter mirror sub-assembly*1 |
| G97-10 (CANH) - G97-21 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 200 Ω or higher | Multiplex tilt and telescopic ECU*2 |
- *1: w/ Headup Display System
- *2: w/ Power Tilt and Power Telescopic System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to No. 8 CAN junction connector) | B |
| NG (Line to combination meter assembly) | C |
| NG (Line to ECU or sensor) | D |
| A | | REPLACE NO. 5 CAN JUNCTION CONNECTOR |
| B | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - NO. 8 CAN JUNCTION CONNECTOR) |
| D | | GO TO STEP 6 |
|
| 5. | CHECK FOR SHORT IN CAN BUS LINES (NO. 5 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
(a) Disconnect the G17 combination meter assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
| *a | Front view of wire harness connector (to No. 5 CAN Junction Connector) | *b | to Combination Meter Assembly |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G97-8 (CANH) - G97-19 (CANL) | Cable disconnected from negative (-) auxiliary battery terminal | 1 MΩ or higher |
| OK | | REPLACE COMBINATION METER ASSEMBLY |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
| 6. | CHECK FOR SHORT IN CAN BUS LINES (ECU OR SENSOR) |
(a) Reconnect all wire harness connectors.
(b) Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.
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| (c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
HINT:
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|
| OK | | REPLACE ECU OR SENSOR |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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